only restart the firewall (iptables) if needed

Signed-off-by: Nico Schottelius <nico@bento.schottelius.org>
use default parameter

Signed-off-by: Nico Schottelius <nico@bento.schottelius.org>
do not generate code when mode = 0xxx format

Signed-off-by: Nico Schottelius <nico@bento.schottelius.org>
++changes(3.0.0) (really!)

Signed-off-by: Nico Schottelius <nico@bento.schottelius.org>